Owing to the high precision and sensitivity of optical systems, there is an increasing demand for optical methods that quantitatively characterize the physical and chemical properties of biological samples. Information extracted from such quantitative methods, through phase and/or amplitude variations of light, can be crucial in the diagnosis, treatment and study of disease. In this work we apply a recently developed quantitative method, called ultraviolet hyperspectral interferometry (UHI), to characterize the dispersion and absorbing properties of various important biomolecules. Our system consists of (1) a broadband light source that spans from the deep-UV to the visible region of the spectrum, and (2) a Mach–Zehnder interferometer to gain access to complex optical properties. We apply this method to characterize (and tabulate) the dispersive and absorptive properties of hemoglobin, beta nicotinamide adenine dinucleotide (NAD), flavin adenine dinucleotide (FAD), elastin, collagen, cytochrome c, tryptophan and DNA. Our results shed new light on the complex properties of important biomolecules.

Deep UV dispersion and absorption spectroscopy of biomolecules.

Supramolecularly assisted modulations in the photophysical properties of the well known and practised antibiotic drug ciprofloxacin (Cpf) with versatile macrocyclic cavitand molecule cucurbit[7]uril (CB7) has been explored under different pH conditions. Both the cationic (Cpf-H+) and neutral (Cpf) forms of the drug exhibits strong binding interaction with CB7. Ground state absorption, steady-state fluorescence, time-resolved emission and fluorescence anisotropy decay measurements documented the host assisted intriguing changes in the photophysical properties of the drug, occurred through the successive formations of the 1:1 and 1:2 (drug to host) inclusion complexes, and thereby causing the intriguing small initial enhancement in fluorescence intensity at lower host concentrations and subsequently leading to a strong fluorescence quenching at higher CB7 concentration. Inferences drawn from the photophysical studies are nicely supported by the results obtained from the 1H NMR measurements. Investigations on the photodegradation studies involving the Cpf-H+ and Cpf forms of the drug, both in the absence and in the presence of CB7 host, revealed that there is a large enhancement in the photostability for both the prototropic forms of the drug, by about 3 times, on their inclusion complex formation with the CB7 host. Observed results from the supramolecular interactions of the ciprofloxacin drug with CB7 macrocycle are suggested to have implications in improving drug stability and in the possible deployments in drug formulations and drug delivery systems.

Supramolecular host-guest interaction of antibiotic drug ciprofloxacin with cucurbit[7]uril macrocycle: Modulations in photophysical properties and enhanced photostability

This study investigated the interaction processes of ciprofloxacin (CIP) with graphene oxide (GO) and reduced GO (rGO) in presence of montmorillonite (Mont) in simulated gastrointestinal fluids The order of CIP adsorption affinity was rGO+Mont > GO+Mont > rGO+Mont+pepsin > rGO > GO+Mont+pepsin > Mont > Mont+pepsin > GO > rGO+pepsin > GO+pepsin in simulated gastric fluid Mont enhanced the adsorption of CIP on GO and rGO due to hydrated Si species coating on GO and rGO in the simulated gastric fluid Meanwhile, π–π interaction between CIP and graphene caused the great shift of two cyclopropyl CH2 and one cyclopropyl in CIP molecules And GO, rGO, and Mont interacted mainly with CIP by COOH groups CIP and pepsin molecules could intercalate and increase the basal spacing of Mont as well After the various interaction systems of adsorbent-adsorbate transferring to the simulated intestinal fluid, CIP was continuously adsorbed by GO and rGO In addition, adsorbed CIP was released from Mont into the solution through electrostatic repulsion The decrease ratio of CIP was the lowest in the GO/rGO+Mont+pepsin systems Therefore, the mixture of Mont and GO/rGO decreased the CIP concentration in gastrointestinal fluid to weaken further antibiotic activity of CIP

Interaction processes of ciprofloxacin with graphene oxide and reduced graphene oxide in the presence of montmorillonite in simulated gastrointestinal fluids

The interaction of aluminum with biomolecular building blocks is a topic of interest as a first step to understand the potential toxic effects of aluminum in biosystems. Among the different molecules that aluminum can bind in a biological environment, phosphates are the most likely ones, due to their negatively charged nature. In the present paper, we combined DFT quantum mechanical calculations with the implicit solvent effect in order to characterize the interaction of Al(III) with these molecules. An extended set composed of a total of 59 structures was investigated, which includes various types of phosphates (monoester, diester, triester-phosphates) and various phosphate units (mono-, di- and tri-phosphate), considering various charge and protonation states, and different binding modes. The goal is to unveil the preferential interaction mode of Al(III) with phosphates in 1 : 1 complexes. Our results reveal that Al(III) prefers to form dicoordinated complexes with two phosphates, in which the interaction with each of the phosphates is of monodentate character. Our results also suggest a high affinity for binding basic phosphate groups, pointing to ATP, phosphorylated peptides, and basic diphosphates (such as 2,3-DPG) as strong aluminum chelators.

Mapping the affinity of aluminum(III) for biophosphates: interaction mode and binding affinity in 1 : 1 complexes.

This is the first study to comprehensively analyze the toxicity of Al coagulants, which are widely present in the effluent of water treatment plants and in natural water in the form of polynuclear Al (e.g., nano-Al13) and mononuclear Al (Alm), on the siphoning efficiency, antioxidant defense system and histological alterations of Corbicula fluminea. The results showed that Alm had a stronger inhibitory effect on siphoning than the nano-Al13 coagulant. For all the selected enzyme indexes, induction by nano-Al13 was more intense in the digestive gland, while that by Alm was more obvious in the gills. Either Alm or nano-Al13 can enlarge the tubule lumen and reduce the thickness of the epithelia of digestive tubules, but nano-Al13 caused more severe damage to the cellular membrane. Inferred from the bright clusters observed by microscopy, granular nano-Al13 enters the digestive gland mainly via swallowing, while gill filtration is another method by which the ionic Alm can enter the clam body. The presence of nano-Al13 and inhibition of enzymes associated with GSH, such as GST and GR, led to the damage of cell membranes. For both Al coagulants, the influence of higher concentrations is more negative. As an effective coagulant, the toxicity of PACl cannot be ignored.

Oxidative stress and histological changes in Corbicula fluminea exposed to nano-Al13 and monomeric Al coagulants

In this study, both experimental and theoretical approaches, including absorption spectra, fluorescence emission spectra, 1H- and 31P-NMR, electrospray ionization mass spectrometry (ESI-MS), pH-potentiometry and theoretical approaches using the BEST & SPE computer programs were applied to study the competitive complexation between ciprofloxacin (CIP) and b-nicotinamide adenine dinucleotide phosphate (NADP) with aluminum (III) in aqueous solutions. Rank annihilation factor analysis (RAFA) was used to analyze the absorption and fluorescence emission spectra of the ligands, the binary complexes and the ternary complexes. It is found, at the mM total concentration level and pH = 7.0, the bidentate mononuclear species [Al(CIP)]2+ and [Al(NADP)] predominate in the aqueous solutions of the Al(III)-CIP and Al(III)-NADP systems, and the two complexes have similar conditional stability constants. However, the pH-potentiometry results show at the mM total concentration level and pH = 7.0, the ternary species [Al(CIP)(HNADP)] predominates in the ternary complex system. Comparing predicted NMR spectra with the experimental NMR results, it can be concluded that for the ternary complex, CIP binds to aluminum ion between the 3-carboxylic and 4-carbonyl groups, while the binding site of oxidized coenzyme II is through the oxygen of phosphate, which is linked to adenosine ribose, instead of pyrophosphate. The results also suggested CIP has the potential to be a probe molecular for the detection of NADP and the Al(III)-NADP complexes under physiological condition.

https://www.mdpi.com/1420-3049/17/8/9379/pdf

Spectroscopy and Speciation Studies on the Interactions of Aluminum (III) with Ciprofloxacin and β-Nicotinamide Adenine Dinucleotide Phosphate in Aqueous Solutions

In this paper, electrochemical tests are applied to investigate the effects of Al(III) and nano-sized tridecameric aluminum polycation (nano- Al13) on aldehyde dehydrogenase (ALDH) activity, by using reduced graphene oxide chemically modified electrodes. The amperometric i-t curves for the oxidation of the enzymatically generated diphosphopyridine nucleotide-reduced disodium salt (NADH) are collected, and the ALDH activity is determined indirectly, depending on the changes of the oxidation current of NADH. The results show that Al(III) and nano-Al13 exhibit effective inhibition on ALDH activity. The proposed mechanism of the effects is explored by means of various analytical techniques, such as fluorescence spectroscopy and circular dichroism. Based on the characterization methods mentioned above, the remarkable activity reduction of ALDH might be ascribed to the conformational changes of coenzyme nicotinamide adenine dinucleotide (NAD+) induced by different aluminum species.

Effects of Al(III) and Nano- ${\rm Al}_{13}$ on Aldehyde Dehydrogenase Activity on Reduced Graphene Oxide Modified Electrode

The aim of this study was to isolate and identify antioxidative peptide from goose liver hydrolysate (GLHP) for ameliorating oxidative stress damage by alcohol in HHL-5 hepatocytes. In this research, the target antioxidative peptides in GLHP were separated, purified, and identified via a tangential flow ultrafiltration system combined with size exclusion chromatography (SEC), ion exchange chromatography (IEC), reversed-phase liquid chromatography (RP-LC), and LC-MS/MS. The results suggested that the amino acid sequence of the target antioxidative peptide for ameliorating alcohol-mediated oxidative stress damage in HHL-5 hepatocytes was Leu-Pro-Leu-Pro-Phe-Pro (LPLPFP), which had a molecular weight of 683.41 Da, and was derived from NADH-ubiquinone oxidoreductase chain 1 in goose liver. In addition, LPLPFP was confirmed to have a satisfactory stability and maintained high hepatic protective activity in a simulated gastrointestinal digestion. Moreover, the mechanism of LPLPFP prevented against oxidative stress damage in HHL-5 hepatocytes was attributed to inhibiting the production of reactive oxide species (ROS) by upregulating genes expression in the Ahr-NQO1 signal pathway. In conclusion, these results indicated that dietary GLHP supplementation could ameliorate alcohol-mediated oxidative stress damage and provide an affordable dietary intervention strategy to prevent alcohol-mediated hepatocyte damage.

/pdf/isolation-and-identification-of-antioxidative-peptide-from-11buwvgs.pdf

Isolation and Identification of Antioxidative Peptide from Goose Liver Hydrolysate to Ameliorate Alcohol-Mediated Oxidative Stress Damage in HHL-5 Hepatocytes

Hai-Yan Wei

Papers

Spectroscopy and Speciation Studies on the Interactions of Aluminum (III) with Ciprofloxacin and β-Nicotinamide Adenine Dinucleotide Phosphate in Aqueous Solutions

Effects of Al(III) and Nano- ${\rm Al}_{13}$ on Aldehyde Dehydrogenase Activity on Reduced Graphene Oxide Modified Electrode

Isolation and Identification of Antioxidative Peptide from Goose Liver Hydrolysate to Ameliorate Alcohol-Mediated Oxidative Stress Damage in HHL-5 Hepatocytes